It varies for me too, but i tend to stick with classical music, jazz, Enya or some lyric-less tunes (if i listen to some of my favourite metal or hard rock bands i'll start singing along in my head and forget what i'm doing).

Although i'm not a fan of house/techno music, lately i've been listening to Daft Punk's Discovery.

I find it interesting in looking at old posts.. as this was a bummer. I was so disappointed in Megadeth's latest album. <-- and that's coming from a die hard Megadeth fan. Well at least there will always be "rust in peace"